1. Field of the Invention
The present invention concerns a method for positioning a motorized positionable patient bed, as well as a patient positioning device for that purpose.
2. Description of the Prior Art
A motorized positionable patient bed is used for positioning a person in an examination with a medical imaging system. The position of the person to be examined is typically varied in steps such that data from a different body region of the person is acquired by the measurement device of the imaging system in the direction of the longitudinal axis of the body. Given each position change a measurement is implemented that is subsequently reassessed in a computerized manner in a diagnosis image. If a series of such diagnosis images (known as a scan) exists, the information of the individual diagnosis images can likewise be converted in a computerized manner into three-dimensional information. A very precise spatially-resolved diagnostic is possible in this manner. Such medical imaging systems are, for example, computed tomography systems and magnetic resonance tomography systems.
Computed tomography systems used are not only to generate diagnoses using the acquired image information, but also medical instruments (for example probes) in the human body can be exactly positioned with the aid of computed tomography. It is typical to initially generate an overview scan for prior planning of the medical intervention. The medical instrument to be positioned shown in a subsequently implemented scan in order to be able to monitor the position of the medical instrument as well as to be able to implement planning for the further procedure. For an optimally exact positioning of the medical instrument a multiple repetition of this procedure is often necessary.
A measurement (data acquisition) device of the imaging system often surrounds the person in a quite close radius such that a medical intervention for positioning a medical instrument can be implemented only in an uncomfortable manner or cannot be implemented at all. This confinement occurs due to the gantry that is used in computed tomography and the scanner bore in magnetic resonance tomography, which completely surround a body region of the examined person.
For a medical intervention, the person is therefore typically moved out of the measurement device of the imaging system by means of the patient bed sufficiently far that a treating physician can implement the medical intervention without spatial constriction. The movement of the patient bed occurs either by software control or by manipulation of control elements such as a joystick or a pushbutton. After a movement of the patient bed out of its measurement position and the implementation of the medical intervention, the patient bed is moved back into its measurement position again in order to be able to monitor the result of the manipulation by means of a scan.
The same body region of the person to be examined is thereby always measured by means of a scan. The scan is initiated by the treating physician with a further control element, most often a foot switch. In order to approach a measurement position with which data from this body region can be acquired by the measurement device, a treating physician typically notes the position of the patient bed (indicated by a numerical indicator) or learns this position from image information containing position information shown on a display element, and moves toward this position by manipulation of the control elements after implementation of the medical intervention. The resumption of this position, however, normally succeeds only after a repeated movement of the patient bed back and forth, in particular when the control element for the movement enables a number of advancement speeds for the positioning, and the advancement speed is successively increased given a longer triggering of the control element.